1. Field of the Invention
The present invention relates to optical recording media, and more particularly, to a defect management method for an optical recording medium and an optical recording medium using the same, in which a plurality of temporary defect management areas is used for defect management.
2. Discussion of the Related Art
Optical discs are widely used as recording media for storing large amounts of data for long periods of time. Such recording media can be largely divided into two types, including rewritable discs and write-once type discs. In data recording using a write-once type disc, only one write operation can be performed for any given area, while the rewritable disc affords much greater flexibility, particularly in terms of the management of defective areas. A defective area results from a manufacturing flaw in or subsequent damage to the surface of an optical recording medium that precludes recording data on one or more clusters.
If a defective area is found during the recording of data on an optical disc, the data written in the defective area is rewritten on an alternative area assigned by the manufacturer. At the same time, locator information, which is indicative of the defective area and its replacement recording area, is recorded for the defects of a given disc as defect management information in a defect management area (DMA). Thus, data to be recorded on an optical disc may be reproduced even if the disc exhibits defects on the recording surface.
This technique, however, is generally applied to rewritable discs, which allow free access to all data recording areas. Any necessary defect management can therefore be accomplished with a relatively small DMA, which enables high-speed recording. Write-once type discs, on the other hand, require larger DMAs and more complex defect management due to their inherent write function limitations, and as a result, data recording operations typically require much more time.
Meanwhile, a new type of high-density optical recording medium, known as the HD-DVD, has been adopted for recording and storing high-quality audio and video data. An example of an HD-DVD recording medium is the Blu-ray disc, so named due to the use of blue rays (405 nm), which are far denser than the red rays (650 nm) used by conventional DVDs and can therefore store significantly larger amounts of data on standard-sized optical discs. Standardization of this technology is underway, to include standards for a write-once Blu-ray disc (BD-WO) and for a rewritable Blu-ray disc (BD-RE), particularly with regard to the detection and management of defective areas detected during data recording operations.
Importantly, any standardization of defect management for a write-once type disc (e.g., a BD-WO disc) should consider defect management using a rewritable disc (e.g., a BD-RE disc). Thus, the standardization of one should embrace as many common features of the other as possible, to maintain consistency and compatibility while striving for the efficient recording of defect management information to facilitate stable data reproduction operations.
In any event, the management of defective areas is crucial during data recording, particularly for high-density DVDs such as the Blu-ray disc, but current BD-WO standards are inadequate. A unified standard, one that can accommodate the progressive demands of commercial systems for optical data storage, is required.